Solutions for Exercise 1 (2)

• module Star {

• Star[][] trek;

• int[][] enterprise() {

• while (false);

• { return newarray int[]("trek"); }

• }

• int voyager(int x, y) {

• if x > y

• int z = 2;

• else

• return enterprise()[-!y];

• return !-5;

• }

• }

• module LinearAlgebra {

• int scalarProduct(int[] xs, int[] ys, int n) {

• if (n == 0)

• return 0;

• else

• return xs[n-1] * ys[n-1] + scalarProduct(xs,ys,n-1);

• }

• int scalarProduct2(int[] xs, int[] ys, int n) {

• int result;

• result = 0;

• while (n > 0) {

• n = n - 1;

• result = result + xs[n] * ys[n];

• }

• return result;

• }

• void nextToken() {

• while (ch <= ' ')

• nextCh();

• switch (ch) {

• case EOF_CH:

• token = EOF; break;

• case '-': case '+': case '0': case '1': case '2': case '3':

• case '4': case '5': case '6': case '7': case '8': case '9':

• buf.setLength(0); buf.append(ch);

• if ((ch == '-') || (ch == '+')) {

• nextCh(); if ((ch < '0') || (ch > '9')) error("missing number");

• } else

• nextCh();

• while ((ch >= '0') && (ch <= '9')) {

• buf.append(ch); nextCh();

• }

• token = NUM; chars = buf.toString(); break;

• case '<':

• nextCh();

• if (ch == '=') {token = LTEQ; nextCh();} else token = LT;

• break;

• ...

• default:

• error("illegal character: " + ch);

• }

• }

• What about comments?